"The last acceptable prejudice", P. Jenkins. The left in particular hates Catholics. But, the modern political left in the U.S. has its historical roots in both the pro-slavery Democrats as well as the anti-immigrant Know Nothings (you could say they took from the worst both the north and the south had to offer) -- hatred and disdain for "white ethnics and non-white people" is deeply ingrained into them (don't look at their words, look at what their actions towards the same have been). So, it isn't just an anti-Catholic thing (back in the day they hated German immigrants...who are hardly all Catholic...they used to call them "brown"! what a joke, huh?).